Improved warning message.

Impoved the warning message when the dp buffer was filled.

worker.cc

@@ -125,12 +125,15 @@ static void *worker_thread_start(void *data)
 		&wrkctrlstate.kernel_launch_count, &filled_dp_buffer);
     }
 
-#ifdef SAVE_DPS
     if (filled_dp_buffer) {
+#ifdef SAVE_DPS
 	cerr << "Warning: The device dp buffer was filled, so some points were not recorded.\n";
 	cerr << "These points will not be reproducible.\n";
-    }
+#else
+	cerr << "Warning: The device dp buffer was filled, so some points were discarded.\n";
+	cerr << "For better efficiency, reduce the number of threads or the dpfreq, or increase the buffer size.\n";
 #endif
+    }
 
     return NULL;
 }